<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>构造函数</title>
</head>
<body>
	<script type="text/javascript">
	var reg = new RegExp("\\bis\\b","g");
	alert('He is a boy. This is a dog. Where is she?'.replace(reg,'Is'));
	</script>
</body>
</html>